<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script crossorigin src="https://unpkg.com/react@18/umd/react.development.js"></script>
    <script crossorigin src="https://unpkg.com/react-dom@18/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
</head>

<body>
    <div id="root"></div>
    <script type="text/babel">
        class Root extends React.Component{
           constructor()
           {
             super();
             this.state = {
                message:"hello word"
             }
             this.handleClick =  this.handleClick.bind(this);
           }

           handleClick()
           {
               this.setState({
                message: this.state.message === "hello world"?"hello react":"hello world"
               })
           }

           render()
           {
               return (
                 <div>
                    <h2>{this.state.message}</h2>
                    <button onClick={this.handleClick}>修改文本</button>
                 </div>
               )
           }
        }
       
       const root = ReactDOM.createRoot(document.querySelector("#root"));
       root.render(<Root/>);
    </script>

</body>

</html>